This invention relates to a porous electrode for implanation in organic tissue, more particularly a pacemaker electrode.
Porous electrodes for implanation is organic tissue, more particularly pacemaker electrodes, are known from U.S. Pat. No. 4,011,861. They consist of an electrically conductive part, the surface of which can come into contact with body fluids and is completely enclosed by an inert porous material, the pores of which have a diameter of from 0.5 to 1,000 .mu.m. The electrically conductive part may be compact or porous. Platinum, iridium, niobium, indium, palladium, titanium, tantalum, vanadium, tungsten, chromium, cobalt, stainless steel, alloys of some of these metals, and carbon, are cited as materials for this part. The porous covering may be electrically conductive or electrically non-conductive. When it is electrically conductive it may consist of metal, carbon, a metal-coated non-conductor, an electrically conductive plastic, or the same material as the electrically conductive electrode part it encloses. If it is electrically non-conductive, it may consist of ceramics, aluminium oxide, silicon dioxide, calcium oxide, magnesium oxide, titanium oxide and/or zirconium oxide or a porous ceramic made from such oxides and available commercially under the name Cerosium. The electrodes described are constructed in the form of a spiral member.
U.S. Pat. No. 3,476,116 discloses a tubular electrode for pacemakers consisting of a two-stage housing of dielectric material, such as plastic, which contains a spiral of platinum iridium, the diameter of which is adapted to the diameter of the tube of the respective housing stage. The base of the housing is formed with a 1 mm.sup.2 opening. The housing is filled with an electrically conductive solution, such as aqueous salt solution.